Fusarium brachygibbosum Padwick, Mycological Papers 12: 11 (1945).
Index Fungorum number: IF 286508; MycoBank number: MB 286508; Faceoffungi number: FoF 11683; Figs. 1, 2
Pathogenic on roots of Vigna unguiculata. Sexual morph: Not observed. Asexual morph: Conidiophores 27–58 µm long, carried on aerial mycelium, unbranched or irregularly and/or sympodially branched bearing a terminal phialide. Conidiogenous cells 8–22×2–4 µm, polyphialide, subulate to subcylindical, smooth. Macroconidia 15.2–22 × 2–3 µm, hyaline, slightly curved with five distinct septa, wide central cells, slightly sharp apexes, basal cells with foot like shape. Microconidia rarely observed. Chlamydospores 6–24 µm diam. abundant, spherical o globose, smooth, slightly verrucose, formed terminally or intercalary in chains of two or three, wall 1–1.5 µm.
Culture characteristics – Colonies on PDA reaching 90 mm at 28 °C after 14 d in 12/12 dark, colonies appeared white to pink with abundant aerial mycelium.
Materials examined – India, Karnataka, Mysuru, Doddamaragowdanahally, diseased root of cowpea (Vigna unguiculata (L.) Walp. Fabaceae), May 2019, S. Mahadevakumar & Y.S. Deepika (UOM-IOE 19/16), living cultures CPFb1, CPFb2, CPFb3, CPFb4.
Hosts – Wide host range, including Allium, Beta, Cannabis, Citrullus, Citrus, Euphorbia, Glycine, Gossypium, Helianthus, Nerium, Nicotiana, Phoenix, Plasmopara, Prunus, Sansevieria, Sorghum, Triticum, Vigna and Zea (Farr and Rossman 2022; this study).
Distribution – Wide geographical range, including in Australia, Azerbaijan, China, India, Iran, Malaysia, Oman, Qatar, Soudi Arabia, Tunisia, Turkey and United States (Farr and Rossman 2022; this study).
GenBank numbers – CPFb1– MT804589 (ITS), OM938019 (tef1) CPFb2– MT804590 (ITS), OM938020 (tef1) CPFb3– MT804591 (ITS), OM938021(tef1) CPFb4– MT804592 (ITS), OM938022 (tef1)
Notes – Fusarium brachygibbosum is known to associated with 19 host plants of which two records are represented from India (Sorghum vulgare, Plasmopara viticola) (Farr and Rossman 2022). This is the first record of F. brachygibbosum recorded on Cowpea (Fabaceae) from India (new host record) (Fig. 3).
Figure 1 – Cultural and morphological features of Fusarium brachygibbosum: a–c pure cultures of F. brachygibbosum isolated on PDA medium (12 days old) (a–b Front view, c– reverse view); d–h Microscopic view of F. brachyggibosum conidia structures observed under compound microscope. Scale bar: d–h=20 µm
Figure 2 – Morphological features of Fusarium brachygibbosum: a–b Conidial morphology of F. brachygibbosum under compound microscope; c–d hyphal structures and chlamydospores of F. brachygibbosum; e–f a single macroconidium enlarged. Scale bar: a–d 50 µm; e–20 µm; f– g 10 µm
Figure 3 – RAxML phylogenetic tree generated from tef1 sequence data of Fusarium sambucinum species complex. Maximum likelihood bootstrap support≥75% (in blue) and BYPP≥0.95 (in green) are indicated on the branches. Ex-type and epi-type cultures are indicated in bold with ‘T’ and ‘ET’